Last year, President Obama’s speech to the United Nations was full of promise and determination to advance Palestinian statehood through negotiations with Israel. This year, his address was about lowering expectations and a dispiriting realpolitik as the president spoke of how “peace is hard” and vowed to veto the Palestinians’ bid for statehood if it came to a Security Council vote.

Mr. Obama had no choice but to stand by Israel, this country’s historic ally. And we agree that a negotiated deal is the only way to ensure the creation of a viable Palestinian state, guarantee Israel’s security and build a lasting peace. But there should be no illusions about the high cost both Israel and this country will pay if this stalemate is allowed to drag on any longer.

There is plenty of blame to go around. The main responsibility right now belongs to Prime Minister Benjamin Netanyahu of Israel who refuses to make any serious compromises for peace. He appears far more concerned about his own political survival than his country’s increasing isolation or the threat of renewed violence in the West Bank and all around Israel’s borders.

The Palestinian president, Mahmoud Abbas, who is understandably frustrated, has forced a process that holds high risks for him as well. The bid to the United Nations is hugely popular among Palestinians. But he may find it hard to contain their disappointment when it becomes clear that maneuvering in New York cannot deliver a state on the ground.

President Obama and his aides have misplayed the diplomacy from the start; they promised “confidence building” measures they couldn’t deliver and lost sight of the bigger deal. But we are sure there can be no solution without strong American leadership.

What happens now? On Friday, Mr. Abbas is expected to submit an application for statehood to the Security Council, triggering a review process with no definite timetable. Washington hopes this will buy room and time to get the two sides into substantive talks.

The United States and its allies are going to have to be ready to push both the Israelis and the Palestinians hard. After months of talking, the so-called Quartet — the United States, the European Union, Russia and the United Nations — still has not agreed on a set of negotiating guidelines on borders, security, refugees and Jerusalem.

There is no mystery to what a final deal would look like, just a lack of political courage to push it to the end. In The Times on Thursday, Ehud Olmert, Israel’s former prime minister, wrote about his own 2008 peace offer to Mr. Abbas, which would have led to the creation of a Palestinian state on territory equivalent to the pre-1967 West Bank and Gaza Strip, with mutually agreed land swaps.

Mr. Olmert said his ideas were never formally rejected by Mr. Abbas, who, despite recent assertiveness, suffers from an inability to make decisions. When Mr. Netanyahu took office, Mr. Abbas wanted to pick up where Mr. Olmert left off, but Mr. Netanyahu wanted to start fresh.

The United States and its partners should put a map and a deal on the table, with a timeline for concluding negotiations and a formal United Nations statehood vote. The proposal must be bold and fair and backed by the Security Council and the Arab League. And they need to help sell it to the Israeli and Palestinian people — not just politicians.

There is still some time left to avoid a complete diplomatic train wreck. But not a lot of time.